Is there something that can trim a sync signal?

[TechnicalMonkey]

I am in the middle of trying to capture output from a Naomi 1/2 using the Key Digtal Systems' Clear Color 3 and a ADSTech Pyro A/V Link. The problem is that the Naomi 1/2 has an out put of 15.85kHz which fills up the frame buffer too fast. I really don't want to put 2 layers of scan converters because this will look really ugly really quickly. I can't use just the downscan converter since the monitors would have to work at 31.68kHz which the monitors in use don't even go past 25kHz. A lot of the signal is a waste since the actual picture is 448 lines most of the black is on the top and a few lines on the bottom.

I just want to be able to use one transcoder to capture the video without having to resort to 2 scan converters. Any help would be appreciated.

Thank You

P.S.: Below is a link of a sample of what I get right now.

http://rapidshare.de/files/12145389/naomitest002-2.avi.html

It's Kagemaru vs. Wolf in Virtua Fighter 4: Final Tuned rev.B